The present invention is concerned with a gyroscope universal flexure hinge assembly of the type described, for example, in U.S. Pat. No. 3,856,366. The patent describes a flexure hinge suspension assembly for use in a free-rotor displacement-type gyroscope, and which comprises an inner tubular hinge member and an outer tubular hinge member concentrically nested within one another and generally coaxial with the spin axis of the gyroscope.
In the assembly to be described herein, and in the assembly described in the patent, the flexure blades are formed in each of the tubular hinge members by corresponding pairs of closely spaced apertures which extend through the wall of each hinge member. Then, when the two tubular hinge members are nested within one another and rigidly fastened to one another, an appropriate orthogonal alignment between the flexure blades of the inner and outer members is established so that two tubular hinge members may operate in their intended manner, i.e., to support the flywheel against torsional and radial displacements relative to the spin axis and against axial displacements along the spin axis.
The prior art flexure hinge assembly of the type described in the patent has a major disadvantage. If the suspension assembly is constructed according to the patent, the flywheel would have very high torsional stiffness about axes perpendicular to the spin axis. The spin axis of the rotor would essentially be locked in alignment with the shaft axis of spin. In order for the rotor to have two degrees of angular freedom relative to the shaft the centers of rotation of the hinges along each suspension axis must be coincident (colinear or aligned). The prior art hinge assembly described in the referenced patent above shows that the centers of the hinge pairs which form each axis are purposely not aligned. This misalignment causes very high torsional stiffness for the flywheel angular displacements about axes perpendicular to the spin axis, a condition which is quite contrary to the intended operation of the gyroscope suspension.